Metering low-velocity fluid-flows.



A. R. DODGE.

METERING LOW VELOCITY FLUID FLOWS.

APPLIOATION FILED NOV. 9, 1912.

1,108,721. Patented Aug. 25, 1914.

2 SHEET S-SHEBT 1.

Figm

/ I Inventor:

U .fiustm RDod ge,

- fF u r 26 A-WW Hisoqttorney.

A. R. DODGE.

METERING LOW VELOCITY FLUID FLOWS.

APPLICATION FILED NOV.9, 1912.

1,108,721. Patented Aug.25,1914.

2 SHEETSSHEET 2.

Fig.2.

Witnesses: Inventor:

- I b oqustinRDodge, W4 21 7 H f His o ttorneg- UNITED STATES Pn' rENTOFFICE.

AUSTIN R. DODGE, 0F SCHENE'CTADY, NEW YORK, ASSIGNOR T0 GENERAL ELECTRICCOMPANY, A CORPORATION OF NEW YORK;

Specification of Letters Patent.

Patented Aug. 25, 1914.

Application filed November 9, 1912. Serial No. 730,351.

To all 'wkomit may concern: I

Be it known that I, AUsTIN R. DODGE, a citizen, of the United States,residing at Schenectady, in the county of Schenectady, State of New-.York, have invented certain new and useful Improvements in MeteringLow-Velocity Fluid-Flows, of which the following is a specification.

This invention relates to apparatus for determinin the varyingquantities of fluid flowing ,t rough a conduit during equal incrementsof time, and its, objectis to ascertain accurately what the flow is,evenwhen the velocity is low. In that type of flow meter in which theindications are produced by a pressure-difference device in the fluidconduit, there is liability of error when the flow is small, because thevelocity is lowand the: pressure-difference slight, so that variationsare'not. so. readily discernible. My invention aims to remove thisobjection by providing a branch'conduit; of considerably smalleroross-sectionthan the main. cone duit, so that a'smallanddefinitepropjortion.

- of the fluid will. pass through it. A pressure-difference nozzle orthe-like is located in the branch conduit, and themain conduit. isprovided with ashut-ofi valve-.which-is' closed by automaticallyactingmeanswhen the fiuid flow and velocity drop to a predeterminedminimumu The closing. of-

preferably a sliding, gate. valve 8. Means I are provided forclosing-this valveby power, such ast'he motor shown, comprising a cylthe main conduit compels all the fluid to flow through the branchconduit, and inasmuch asthis is of smaller area, the velocity. will becorrespondingly increased and the indication correspondingly improved.

For a consideration of' what I believe to. be novel and myinvention,attention.- is di. rected to the accompanying description and claimsappended thereto.

In the accompanying drawing, Figure 1 is j a diagrammatic representationof one embodiment of my inventionrFig. 2 is a simi lar view of amodification, andFig. 3 is a' diagrammatic view of a modified'form ofavalve-motor controlling mechanism. r

Referring to Fig. 1, the conduit 1 divides. at 2 into a large' or main.branch 3 and a: small or shunt branch L. The fluid arriving at the point2 will divide between the two branches in exact proportion totheir-area's ing a U-shaped column of mercury. :,.a

sliding pointer 7% extending over a drum 7 having a suitable scalethereon, shown by the curved lines, plotted in suitable terms as forexamplepound's per hour forv steam,

cubic feet per minute? for air, or gallons per ;m 1nut e for l1quids.--In service the pointer 1s ad usted vertically to register with theupper-end of the left hand leg of the-mercurycolumn and the indicationof the meter is read by comparing the pointed end of the,

pointer with the curved lines on the drum. So long asthe two branchconduits 3 and 4 are open, themeter will function as usual, the velocityof the fluid-being the same in both branches, and the meter being cali-.

brated for aconduit the size ofboth com- ,bined.

:Inthe main branch 3- is a shut-off valve,

and a; complete closure thereof in the other. It isnotintended that thevalve shall occupy intermediate positions.v The movement ofthe. pistonis controlled by a regulator such as a pilot valve 12,'preferably of the"piston type,iworking'in a'valve chest 13 and.

contr'ollin ports 14: leading to the ends of tappeta-rmf- 15 on thepiston rod 11 which plied to the. valve chest through two. pipes -1'8.,19, which open into. said chest at such.

; the cylin er. vThe valve is actuated by a the motive fluid throughsaidother pipe.

It will be observed that the distance betweenlthe collars 16 isconsiderably greater than the thickness of the tappet arm, ,.,In other,

words thereislost motion between the arm and collars. This is importantbecause the gate valve 8 must not be opened and closed for minorvariations in 'flow pf the fluid being meterednbut only when asubstantial and predetermined change takes pla'cei The col-v lars-areadjustable on ,thewalv'e-spindle so that the proper action of theva lvecan be efi'ected. 1 2 i w Thezsupply-of -fiuid pressure to the motor iscontrolled by a 'means responsive te"varia tions; in the rate of fiow ofthe -fluid' being metered and consistingof a; flexiblediaphragm 2Oinclosed in a'casin'g 21,{-which it divides into upperand lower chambersw and 'y. The pipe 18 comiects with the chem berwrand the pipe 19 witl'rthe-chamber 3 Valves 22, 23,"suitably.attached to the diaphragmrespectively controlthe pipes 18,- 19 .the arrangement Being such-'-that when one is open the other will be-closed. .Springs 24, 25 :urgetheevalvs toward their seats. A strong spring"26-'iin' the chamber ywillclose the upper valve 22., ifthe pressure inthe chamber :Iw; drops to apredetermined minimum.

. A pressure-difierence nozzle 27 *r'esponsive to variations in therate" of flow of th'e' fluid being metered is insertedin the branch"con-- duit 4, having its leading side connected by pipe 28 with thechambers? audits trailing side connected by pipe""29 with the chamher y.I

. "The operation is as follows: Ass uming' a considerable flow of fluidin the conduit,the pressure in the chamber as will "cause the diaphragmto-open the valve 22 and admit 1 branch 3. 1 The parts'will'rem'ain in,-this positionuntil the flow drops to a point wherefluidtothe valve'chestthrough the pipes 28 and 18, from which it flows to the upper end of thecylinderv9-and forces down the piston 10 to open the gate "valve 8 inthe main the pressure in chamber leis overbalanced by thespring-','26-,' which at once'forces up the diaphragm,= -closes thevalve 22, and

opens the valve-.23. Thisadmitspressure from; the pipe 29,-"cha1nber y;and pipe 19 to the motor, and the'parts finally' 'a-ssume the positionshown Fig. 1, with the valve 23 open, the pilot valve 12 raised, thepiston at the upper end of the cylinder,and the'g'ate' valve c1osed.-'All the fluid mustnow flow: through the smallbranchhonduit 4, and

though it s-quantity may small, yet the reduced area through which itmust pass ra1sesnts velocity to a. oint vvherethemeter small varla ions.

is a gate-valve 30- in the branchmain aoperatedbya" piston 31inacyl'inder 32', whose ports-"33 are connected with the valve chest atpoints substantially opposite the openingswhich lead to the ports; 14ofthje motor 9.' The passages was ports 33, however; are "crossed, I so1 that the i-motor's "operate in opp'e'site directions, the valve 30,:opening when the valve 8 closes. Theres'ult of: this arrangementia!that during normal condi tions, all the fluid passes thr'ou h the m'aili conduit, and none-through the ranch coh duit, the latter cominginto use only "when the fluid flow drops to such a point that itsvelocity in the main conduit is too low to in fluence the meterproperly;The nozzle '34 for the regulator'is placed in the main: conduit inadvance of the junction there with of the branch conduit The meter ,isconnected with' two nozzle-plugs 35, 36, one in the main and the otherin :thebranch conduit so that the ineter lwill- :alwaysbe inserViceirrspctive/of which conduit is in [service This meter is hereshown as'being gofthe same construction as the one showir inT Fig; 1 andthe 5% same reference characters lhave been applied to correspondingparts". M 1 ,In=Fig 3 isshown amodified form of j governingmechanismwfor the valve raethat= .in'g motor which possesses theadvantage-of.

,simplicity and reliability "in. operation. .20

i indicates "the "diaphragm" contained'a'ina cas-. ging. 21..Thechamberw in the 'upperside of ithe diaphiagm'is'connected.by thepipeY28' to theleadingside ofwnozzle' 27-: and .:-the

chamber y to'ithe trailing side of said nozzle as before; "Under thediaphragmiisa' coiled compression spring 26. Attachedto the diagphragmis a; rod" 37 thatzp'asses :through a fsuitable stufiing box in thecasing and "is attached toithe'tappet lever 38 which is 'piv'ot a'lly'supported on a bra'elaretcarriedtloy, the 7valvewact'uating' motora'Thev'motor' com= Eprises a cylinder9 anda' piston -10, the;latter:

beiii'gfconnected to a shut'ofl valve .in-one of themains. 'The motoris" controlled; by a pilotivalve12- which. is actuated by-ithe taplpetlever 38 in.re'sponse to "movements of the diaphragm, there beinglost-motion between said lever and the stops 16 on the valve' stem "asbefore and for the samepurpose. The fluid under pressure for actuatingthe piston is supplied by the pipe 39 leading from the main to bemetered.

A fluid meter of the character described "available. It is on thisaccount that the nozzle 27 is provided so that the movements of the.valve can be accomplished without imposing any load whatsoever on themeter and hence without interfering with the accuracy of the meterindications. The valve 8 may be arranged to close under anypredetermined condition by properly adjusting the parts. As an exampleit may be made to closewhen the rate of flow has been reduced toone-quarter or one-third the normal flow. These figures are merely givenas an illustration and not as a limitation of my invention since specialcases may require special adjustments.

In accordance with the provisions of the patent statutes, I havedescribed the principle of operation of my invention, together with theapparatus which I now consider to represent the best embodiment thereof;but I desire to have it understood that the apparatus shown is onlyillustrative, and that the invention can be carried out by other means.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is 1. Means for accurately measuring the flow of fluid comprisingparallel flow conduits of different cross-sectional areas, a meter,means for creating a pressure difference responsive to changes in therate of flow of the fluid passing through said conduits and constantlysubjecting said meter to the effects thereof, a valve for shutting oflone of the conduits when the rate of flow of fluid falls below apredetermined value, and means responsive to changes in the rate of flowof the fluid being metered and independent of the meter for actuatingsaid valve.

2. Means for accurately measuring the flow of fluid comprising a largeand a small conduit arranged for parallel flow, a meter, meansresponsive to changes in the rate of flow of the fluid in the smallconduit for causing the meter to act, avalve for putting the largeconduit into and out of service, means for actuating the valve, andmeans in the small'conduit and acting independently of the meter tocontrol said valve actuating means.

3. Means for accurately measuring small flows of fluid, consisting of alarge conduit and a small branch conduit, a flow meter, a nozzle plug inthe small conduit connected to the meter, a valve in the large conduit,

a motor for actuating saidvalve,va pressure? difference device; in thestream of fluid to be metered, and a difi'erential pressure regulatorconnected with said device and con.- trolling said motor. v T

4; Means for accurately measuring small flows of fluid, consisting of alarge conduit and a small branch conduit, a flow meter having a nozzleplug in the small conduit,

a.-valve in the large conduit, a motor for actuating said valve, apressure-difference dev ce in the fluid stream, a casing having adiaphragm formlng two chambers communicating with saidpressure-difference device, and valves controlled by said diaphragm foradmitting fluid pressure from said chambers to said motor.

5. The combination of parallel flow conduits of differentcross-sections, a flow meter, a device responsive to changes in the rateof fluid flow located in the smaller conduit and conveying fluid underpressure to the meter, a valve for shutting ofl one of said conduits, amotor for actuating said valve, a member that is moved in response tovariations in the rate of flow of the fluid being metered, and a meansactuated by said member controlling the motor.

6. The combination of parallel flow conduits of difl'erentcross-sections, a flow meter, a device responsive to changes in the rateof fluid flow located in the smaller conduit and conveying fluid underpressure to the meter, a valve which has an open and a closed positionfor shutting ofl one of said conduits, a. fluid motor for actuating saidvalve, a pilot valve for the motor,"a movable member sensitive topressure variations for moving the pilot valve, a device for creating apressure difference that varies in response to variations in the rate offlow of the fluid being metered, and conduits for conveying saidpressure difference to opposite sides of said member.

7. In combination, a pair of conduits, one of which is smaller than theother, a meter sensitive to changes in the rate of flow of fluid passingthrough the smaller conduit, said meter being calibrated for a conduitequal in cross-sectional area to both of said conduits, a valve in thelarger conduit, a

motor for actuating said valve, a regulator valve for shutting ofi oneof the oonduits In witness whereof, I-. have hemi1'nto 'set my hand this8! ;h day of Hovnmber 1912. AUSTIN DODGE,

jacting said met r to the efl Qts themef, a

when the) rate of flow of fluid falls below a predetermined value, andmeans responsive to changes in' the rate of fiow of the fluid beingmebqi'ed and independent of the meter for actuntmg said valve.

withessez- BENJAMIN B. HULL, HELEN ORFORD."

